剑指offer 28. 字符串的全排列

//题目：输入一个字符串，输出字符串的全排列//解法：确定字符串的第一个字符，然后递归求之后字符的全排列public class Main {public static void main(String[] args) throws Exception {printAllSeq("abc");}public static void printAllSeq(String str){if(str == null){return;}char[] input = str.toCharArray();printAllSeqHelper(input,0);}public static void printAllSeqHelper(char[] input, int begin){if(begin == input.length-1){System.out.println(input);}else{for(int i = begin;i<input.length;i++){char temp = input[begin];input[begin] = input[i];input[i] = temp;printAllSeqHelper(input,begin+1);temp = input[begin];input[begin] = input[i];input[i] = temp;}}}}